:root{--brand:#B4421F;--ink:#211C1A;--muted:#5E5550;--bg:#FBF7F2;--card:#fff;--line:#E6DDD3;--accent:#264653}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--ink);font-family:-apple-system, BlinkMacSystemFont, "PingFang SC", "Noto Sans SC", "Microsoft YaHei", "Hiragino Sans GB", sans-serif;line-height:1.7;font-size:16px}
.wrap{max-width:760px;margin:0 auto;padding:0 16px}
a{color:var(--brand)}
.skip{position:absolute;left:-999px;top:0}.skip:focus{left:8px;background:#fff;padding:8px;z-index:9}
header.top{background:#fff;border-bottom:1px solid var(--line)}
header.top .wrap{display:flex;align-items:center;justify-content:space-between;gap:8px;min-height:52px;flex-wrap:wrap}
.logo{font-weight:700;color:var(--ink);text-decoration:none;display:flex;align-items:center;gap:8px;min-height:44px}
.logo .dot{width:14px;height:14px;border-radius:50%;background:var(--brand)}
nav.main{display:flex;gap:4px}
nav.main a{color:var(--muted);text-decoration:none;padding:10px 8px;min-height:44px;display:inline-flex;align-items:center}
nav.main a[aria-current]{color:var(--brand);font-weight:700}
h1{font-size:26px;line-height:1.3;margin:14px 0 6px}
.answer{margin:0 0 10px;color:var(--muted);font-size:15px;line-height:1.6}
.crumb{font-size:14px;color:var(--muted);margin-top:8px}.crumb a{display:inline-flex;align-items:center;min-height:40px;min-width:40px}
.tool{background:var(--card);border:1px solid var(--line);border-radius:16px;padding:12px;margin:0 0 20px;font-variant-numeric:tabular-nums}
.readout{display:flex;align-items:center;justify-content:space-between;gap:6px}
.step{flex:0 0 auto;width:48px;height:48px;border-radius:12px;border:1px solid var(--line);background:var(--bg);font-size:17px;color:var(--ink);font-variant-numeric:tabular-nums}
.num{flex:1;text-align:center;min-width:0;display:flex;flex-direction:column;align-items:center}
.bpm{font-size:52px;line-height:1.05;font-weight:700;border:0;background:none;color:var(--ink);padding:0 4px;min-width:96px;font-variant-numeric:tabular-nums;font-family:inherit}
.bpm-in{font-size:40px;width:120px;text-align:center;border:2px solid var(--brand);border-radius:10px;font-family:inherit}
.unit{font-size:13px;color:var(--muted);line-height:1.3}.tname{font-size:14px;color:var(--brand);min-height:1.4em;line-height:1.4}
.slider{width:100%;margin:6px 0 4px;height:40px;accent-color:var(--brand)}
.dots{display:flex;flex-wrap:wrap;justify-content:center;gap:6px;margin:2px 0 8px}
.bd{width:40px;height:40px;border-radius:50%;border:2px solid var(--line);background:#fff;color:var(--muted);font-size:13px;font-variant-numeric:tabular-nums}
.bd.l2{border-color:var(--brand);color:var(--brand);font-weight:700}.bd.l0{opacity:.4;border-style:dashed}
.bd.on{background:var(--brand);color:#fff}.bd.l1.on{background:var(--accent);border-color:var(--accent)}
.start{display:block;width:100%;height:56px;border-radius:14px;border:0;background:var(--brand);color:#fff;font-size:20px;font-weight:700;letter-spacing:2px;font-family:inherit}
.start.on{background:var(--accent)}
.grid{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin:12px 0 6px}
.fld{display:flex;flex-direction:column;font-size:13px;color:var(--muted);gap:2px}
.fld select,.fld input[type=number]{height:44px;border:1px solid var(--line);border-radius:10px;background:#fff;font-size:16px;padding:0 8px;font-family:inherit;color:var(--ink)}
.fld input[type=range]{height:44px;accent-color:var(--brand)}
.row{display:flex;gap:8px;align-items:center;flex-wrap:wrap;margin:8px 0}
.row button,.tap{height:44px;padding:0 14px;border-radius:10px;border:1px solid var(--line);background:var(--bg);font-size:15px;font-family:inherit;color:var(--ink)}
.tap{background:var(--accent);color:#fff;border-color:var(--accent)}
.tapout{min-width:80px;font-weight:700}
.chk{display:inline-flex;align-items:center;gap:6px;min-height:44px;margin-right:12px;font-size:15px}
.chk input{width:20px;height:20px;accent-color:var(--brand)}
.chips{display:flex;flex-wrap:wrap;gap:8px;margin-top:8px}
.chip{min-width:56px;height:40px;padding:0 12px;border-radius:20px;border:1px solid var(--line);background:#fff;font-size:15px;color:var(--ink);display:inline-flex;align-items:center;justify-content:center;text-decoration:none;font-variant-numeric:tabular-nums;font-family:inherit}
.chip.jog{border-color:var(--brand);color:var(--brand)}
.remain{text-align:center;margin:8px 0 0;font-size:18px;font-weight:700;font-variant-numeric:tabular-nums}
.content h2,.faq h2,.related h2,.prose h2{font-size:20px;margin:26px 0 8px;line-height:1.4}
.qa h3{font-size:17px;margin:16px 0 4px}.qa p{margin:0}
.cards{list-style:none;padding:0;margin:0}
.card{display:block;background:#fff;border:1px solid var(--line);border-radius:12px;padding:12px 14px;text-decoration:none;color:var(--ink)}
.cn{display:block;font-weight:700;color:var(--brand)}.cd{display:block;color:var(--muted);font-size:14px}
.muted{color:var(--muted)}
footer{margin-top:36px;border-top:1px solid var(--line);background:#fff;font-size:14px;color:var(--muted)}
footer .wrap{display:flex;flex-wrap:wrap;gap:4px 14px;align-items:center;padding-top:8px;padding-bottom:16px}
footer a{color:var(--muted);display:inline-flex;align-items:center;min-height:40px;min-width:40px}
.flash{position:fixed;inset:0;background:var(--brand);opacity:0;pointer-events:none}
.flash.go{animation:fl .12s ease-out}
@keyframes fl{from{opacity:.55}to{opacity:0}}
[hidden]{display:none!important}
@media (min-width:700px){h1{font-size:32px}.bpm{font-size:64px}.grid{grid-template-columns:repeat(4,1fr)}.tool{padding:18px}}
@media (prefers-reduced-motion:reduce){.flash.go{animation-duration:.2s}}